Automotive chassis which use nodes or connecting members to hold together extruded light metal or cast metal frame sections are well known in the art. Examples of automotive chassis using nodes to connect tubular frame sections or elements are shown in Hasler et al (U.S. Pat. No. 4,618,163) and UK Patent No. (GB 2 049 567).
In Hasler et al the frame elements comprise cast metal or extruded light metal rods. The ends of the frame elements are aligned and fitted within a conforming receiving ends of connecting members or nodes. The openings for the doors and windscreens are formed by the nodal connection of several cast metal frame elements and by the segments of the node elements which also face the openings. This results in the formation a joint for every union between a node element and a frame element Thus, transitional regions between adjoining frame elements contain at least two joints because of the node element. Since a portion of each node element also forms a part of the boundary of each opening, it is difficult to produce an exact contour curve for the openings To ensure an exact contour curve, a precise fit of the node to each receiving end of an abutting frame element is required, as well as a stable fixation of the node to each connected frame element during the assembly process. This method results in a labor intensive and costly assembly technique.
In the UK Patent, the frame elements are round tubular girders which are held together by a tubular node elements or lugs. The connectors have tubular flanges for sleeve-like connection to corresponding girder ends. As in Hasler et al, a circumferential joint is formed by the union of each girder to a connector so that there exists at least two joints for every transitional region between adjoining girders. As above, this technique results in an undesirable number of joints along the boundary curves of the frame which define the seating surfaces for the windscreen and door openings thus rendering the final assembly of a chassis having smooth contour curves difficult.
Accordingly, there is a definite need in the art for an improved node-connected motor vehicle chassis wherein the node elements do not form part of the seating surfaces for the windscreens and doors so that the number of joints in these boundary areas of the chassis is reduced by half, and a smooth contour curve for each transitional region is achieved. There is also need for a method of construction of such a motor vehicle chassis which is simple and cost effective to implement.